Parts for your 2021 Mitsubishi Asx-Temperature sensors

2021 Mitsubishi ASX Temperature Sensors — What They Do and How to Look After Them

Temperature sensors are absolutely fitted to the 2021 Mitsubishi ASX. Factory service information for the ASX/RVR/Outlander Sport platform documents multiple sensors, including the engine coolant temperature (ECT) sensor in the engine control section, an intake air temperature (IAT) element (typically integrated with the MAF on many trims), ambient and evaporator sensors in the HVAC diagnostics, and a transmission fluid temperature sensor in the CVT section. These are also reflected by the vehicle’s OBD-II diagnostic capability with DTCs such as P0117/P0118 (ECT), P0113 (IAT) and P0713 (ATF temperature). Mitsubishi MUT-III scan tool procedures and wiring diagrams in the OEM service manual further reference these sensors and their roles.

Here’s what that means for owners and workshops.

The ASX’s temperature sensors quietly keep everything in check, helping the car run sweetly across Aussie and Kiwi conditions. The ECT sensor feeds the ECU live coolant temperature so it can sort cold starts, idle, fuelling and fan control. The IAT sensor trims fuelling and spark based on the air charge. The HVAC ambient and evaporator sensors let the climate control hit the set temp without freezing the evaporator or blasting hot air. In CVT models, the fluid temp sensor protects the transmission, managing pressure and shift strategy when things get hot towing up the Kaimais or cruising in summer heat.

They don’t have a set replacement interval, but they’re service items when faults arise. As part of routine servicing, a tech should:

• Scan for stored or pending temperature-related DTCs and compare live data to reality (e.g., cold start temps should match ambient).
• Check connectors and earths for corrosion, broken locks or moisture under the bonnet and behind the bumper (ambient sensor).
• Inspect harness routing where it passes near fans, belts and hot exhaust components.
• For ECT issues, verify coolant quality and level, poor coolant or trapped air can mimic a “bad sensor”.

Replacement is straightforward when a sensor truly fails. For an ECT sensor, allow the engine to cool, relieve any system pressure, and be ready to top up and bleed coolant afterward. Always fit quality OEM-spec parts, clean the connector, and confirm sealing washers or O-rings are fresh. After replacement, clear codes, run the engine to operating temp, and recheck live data so the radiator fans cut in as expected. For ambient or evaporator sensors, bumper or dash trims may need to come off, if that’s not your thing, a trusted workshop will sort it quickly.

Tell-tales of trouble include hard cold starts, rich running, the temp gauge behaving oddly, cooling fans stuck on or never coming on, weak A/C performance, or CVT “limp” behaviour on hot days. Catching these early with a scan and a quick visual once every 10,000–15,000 km keeps the ASX feeling right as rain.

• Are there different temperature sensors on the 2021 ASX?
• Do temperature sensors need routine replacement?
• Can a DIYer replace the coolant temperature sensor?

Are there different temperature sensors on the 2021 ASX?
Yes. The typical line-up includes the engine coolant temperature sensor, intake air temperature sensor, ambient air temperature sensor for the HVAC, an evaporator temperature sensor, and (on CVT models) a transmission fluid temperature sensor. Each reports to its respective control module to optimise performance and protection.

Do temperature sensors need routine replacement?
No regular interval is specified in Mitsubishi service literature. They’re replaced on condition—when a fault code, dodgy live data or poor drivability/A/C behaviour points to a failed sensor or wiring issue. Regular scans and a quick harness/connector check during service are recommended.

Can a DIYer replace the coolant temperature sensor?
Often, yes. With the engine cold, it’s typically a simple remove-and-refit job, followed by topping up and bleeding the coolant and clearing DTCs. If access is tight or you’re unsure about bleeding procedures, a workshop can handle it quickly.